Modern high speed winders, for winding yarn into yarn packages on bobbins mounted on chucks, generally include two or more rotatable chucks each supporting one or more bobbins. Usually, the chucks are arranged in pairs on opposite sides of the support or housing for a yarn traverse mechanism, with each pair being associated with a common drive roll positioned adjacent the traverse support or housing. While yarn packages are thus being wound on bobbins on one chuck, empty bobbins are placed on the second chuck, which is then in a retracted position. When full packages have been wound on the bobbins on the first chuck, the yarn is transferred to bobbins on the second chuck and the first chuck is retracted and brought to a stop, after which the full packages are removed therefrom.
The fed yarn can be transferred from a full package to an empty bobbin or bobbins on the second chuck manually by a winder operator or attendant, who has to thread the yarn properly for winding on the bobbin on the second chuck. However, such manual re-threading or re-guiding of the yarn, when full packages have been wound, so that the yarn can begin to be wound on empty bobbins, requires a considerable amount of time and, more importantly, a substantial waste of yarn, particularly when yarns are being fed at very high speeds.
A much faster and very highly efficient transfer of yarn from a full package on one chuck of a pair to an empty bobbin on the other chuck of the pair can be effected by the mechanism and method shown, described, and claimed in the inventor's co-pending U.S. Pat. Application, Ser. No. 809,676, filed June 24, 1977, and by the mechanism and method shown, described, and claimed in the inventor's U.S. Pat. Application Ser. No. 690,967, filed May 28, 1976, now U.S. Pat. No. 4,081,149.
With both manual transfer of the yarn from a full package on one chuck to an empty bobbin on the other chuck, or when such transfer is effected by the mentioned methods and mechanisms, the bobbin or bobbins on the previously inactive or idle chuck must be brought into driving engagement with a common drive roll. It is thus necessary to move the previously inactive or idle chuck horizontally, from a retracted position, past the package being wound on the then active chuck and into engagement with the drive roll. The necessity of leaving sufficient clearance for the inactive chuck, with a bobbin or bobbins mounted thereon, to be moved horizontally past the yarn package being wound on an active chuck, has limited seriously the diameter of the package being wound on the active chuck.
This limitation of the size of the packages which can be wound is of great importance when it is considered that the sector of the textile industry which involves man-made fiber production is becoming more competitive year by year with foreign production and more competitive domestically. As a result, there is a great necessity to improve production speeds with a minimum cost of capital equipment. To attain these ends, the man-made fiber processors are constantly expanding their capability of making yarn at higher spinning speeds and with more threads per spinning position. Because there are now more threads per spinning position, the bottleneck for this expansion is the requirement for a winder which has higher speed capability and winds more and larger packages. Thus, in order to be able to use existing spinning processing machinery and plant facilities, such a winder is a key objective as, without such a winder, complete new processing facilities have to be built at continually higher costs for machinery.
A mechanism and method by means of which acceptably larger packages can be wound on existing winders is shown, described, and claimed in U.S. Application Ser. No. 896,051 filed Apr. 13, 1978. In this latter mechanism and method, the inactive or idle chuck, carrying empty bobbins, is moved from a fully retracted position to a "standby" position shortly after the beginning of winding of packages on bobbins on the active chuck. As the package or packages near completion, the inactive chuck is accelerated until its peripheral speed, or that of the bobbins thereon, is substantially synchronous with that of the common drive roll and, as the winding of packages on the active chuck is completed, the inactive or idle chuck, or its bobbins, are brought into engagement with the drive roll and the yarn is then quickly transferred from the packages then being wound to the empty bobbins on the inactive chuck which is now rotating at high speed. As the inactive chuck has already "cleared" the packages then being wound on the active chuck, the packages can be wound to a much greater diameter and a much larger weight of yarn as there is no necessity for providing "clearance" for movement of the active chuck from a retracted position into engagement with the common drive roll.
To effect this, a belt is trained around the drive roll and engaged with a much smaller diameter pulley spaced somewhat from the drive roll toward the retracted positions of the chucks. After the winding of the package has been initiated on one chuck, namely the active chuck, the inactive chuck is brought from the fully retracted position to a position closely adjacent but out of contact with the belt. As the package being wound approaches completion, the inactive chuck is brought into engagement with a "soft" part of the belt so that the inactive chuck may be accelerated to a peripheral velocity substantially synchronous with that of the belt and the common drive roll. As winding of the package is fully completed, the inactive chuck is brought into direct engagement with that portion of the belt trained around the drive roll, or with the drive roll itself, and the yarn is transferred from the fully wound package to empty bobbins on the inactive chuck.
While this latter arrangement satisfactorily solves the problem of winding larger diameter packages on existing winders, it involves bringing a stationary bobbin or a stationary chuck into engagement with a belt travelling at high speed, which has a distinct disadvantage. More specifically, in very high speed winders operating at yarn speeds of 4 to 6 meters per minute, the friction when a bobbin engages the drive roll is such that the bobbin can actually be burned up, in addition to which there is a very high noise level, in the area of over 100 decibels, when the bobbin is engaged with the rapidly moving belt. While this disadvantage is ameliorated to some extent by initial engagement of the chuck or bobbin with a "soft" part of the belt, it is not completely obviated.
It has also been suggested that the inactive chuck could be brought up to speed, before engagement with the drive roll, by the use of a respective turbine or the like driving the inactive chuck. However, with such proposal separate turbine drives for each chuck would be necessary, which is a rather expensive proposition as four such turbine drives would be required for a high speed winder having two pairs of chucks, each associated with a respective common drive roll. An additional disadvantage of this proposal is that, using individual turbines to bring the chucks up to speed, the speed that could be obtained for any given chuck is only approximately the speed of the drive roll, this referring to linear speeds of the chucks and the drive roll, so that there would remain a substantial difference in peripheral velocities between the chuck and the drive roll when the chuck is engaged with the drive roll.